The present invention relates to electromagnetic recording and playback heads for use with magnetic media such as magnetic discs, tape and drums, and more particularly to a head array for high-density writing and reading on flexible magnetic media such as tape or floppy discs.
Prior to the development of my technique for forming electromagnetic heads within a thin web of metallic material, magnetic media read-write heads, particularly for high-performance data-tape applications, were generally fabricated as discrete structures. Head arrays, consisting of read, write and erase heads arranged in a selected format, have heretofore been assembled from a plurality of such separately-fabricated heads. The minimum spacing between heads has been a function of how small individual heads could practically be made and the minimum physical structure on which they could be mounted. Ideally, electromagnetic heads are made as small and closely spaced as possible to reduce weight and achieve high bit density. Industry standard formats for flexible magnetic media currently provide bit densities which enable a single 31/2-inch flexible (i.e., floppy) disc to hold 1-to 2-megabytes of data and enable a reel of 1/4-inch tape to hold 320-megabytes of data.
Smaller, more closely spaced heads could significantly increase the amount of data which a disc or tape can hold. Accordingly, there is a demand for electromagnetic read-write heads which are smaller in size, lower in mass, and which can be employed in smaller head arrays, thereby increasing the density of data stored on magnetic media.
Head structures fabricated in accordance with my invention, that is, heads formed within a thin web of high-permeability magnetic material, are described in the following two patent applications: Ser. No. 07/294,351, filed Jan. 9, 1989, entitled ELECTROMAGNETIC READ/WRITE HEAD, now U.S. Pat. No. 4,984,118, and Ser. No. 531,947, filed Jun. 1, 1991, entitled LINEAR-GAP, NON-GAP-ADJACENT-DISCONTINUITY, ELECTROMAGNETIC READ/WRITE HEAD WITH DIFFERENTIAL PERMEABILITY, filed contemporaneously with this application. In addition to the features claimed in those applications, I have found that my head structure is suitable for developing new, higher density magnetic data storage formats. Because the invention described in this application makes use of head structures and configurations disclosed in the above-identified patent applications, I incorporate the disclosures in those applications herein by reference.